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Abstract

Introduction: Heart failure is a leading cause of morbidity and mortality. Prolonged QRS duration (QRSd), a marker of intra-ventricular conduction delay, has been shown to be associated with worse left ventricular (LV) systolic function, LV dilation and mitral regurgitation as well as with mortality. There are minimal data in the literature on the progression of QRSd over time, and the association with clinical outcomes.

Hypothesis: We hypothesized that the progression of QRSd over time would be associated with mortality and hospitalizations in an outpatient heart failure population.

Methods: Retrospective study of consecutive new adult referrals to a tertiary heart failure clinic over a 1 year period (2012). All patients with a narrow QRSd (defined as <130 ms) were included. Data were collected on demographics, ejection fraction (EF), clinical course and major clinical events. Primary endpoint was mortality and secondary endpoint was heart failure hospitalization.

Results: A total of 147 patients were included, 90 were males (61%). Mean age was 66 years (+/-15), mean EF was 33% (+/- 15) and mean NYHA class 2.2 (+/- 0.9) at baseline. An ischemic aetiology accounted for 50% of the patients. Mean QRSd was 100 ms (+/- 13) at baseline and 119 ms (+/- 25) at last follow-up, which was a mean of 2.5 years from baseline. Death occurred in 27 patients (18%) and there were 114 hospitalizations in 54 patients. Results of univariate regression analysis are presented in the table.

Conclusion: An increase in QRSd over time is associated with increased heart failure hospitalizations and all cause mortality in a tertiary care outpatient heart failure population.